As I reported earlier in this post
I have had 1 issue with WW and the path file access on a default install, that being that, after a reboot, it would not refresh my image because the image in %Programs%\WeatherWatcher\
could were the default that were displayed. I am not sure how they were written there initially (I think it might have had to do with me copying files over under \ProgramData\WeatherWatcher
manually, but after I deleted those files from %Programs%\WeatherWatcher\
the wallpaper has been updating perfectly, and successively through 4 reboots now.
Again, I am not sure if this was a Windows fix or a fix on your end in WW, but for all intents and purposes, WW is fully Vista (Ultimate) compatible, including weather updating and wallpaper updating (and reverting on exit).
I also suspect that , if you don't copy the files over like I did, and ***DON'T RUN WW AT THE END OF THE INSTALLATION PROCESS*** then all will be well, the reason being that the installer runs with admin privileges, and thus is able to, on that first run, write to %Programs%\WeatherWatcher\
whereas subsequent runs of WW are not elevated and thus cannot write to %Programs%\WeatherWatcher\
I have another computer running Vista Home Premium on which I will test this theory here in a bit.